Chimney-cap heater



27, 1930. L BLANCHARD 1,759,830

CHIMNEY GAP HEATER Filed April 15, 1929 /N VENTO R. LESTER. L. BLnmnnnn, y

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Patented May 27, 1930 UNITED STATES PATENT OFFICE LESTER L. BLANCHARD, OF DOVER FOXCROFT, MAINE, ASSIGNOR TO HENRI GREPEAU, OF MONTREAL, CANADA CHIMNEY-CAP HEATER Application filed April 13,

This invention relates to chimneys and particularly to providing means to heat the outlet of the chimney independent of theheat of the gases and smoke passing through such outlet.

The object of my invention is to provide a means of heating the outlet of a chimney when cold and before the gases and smoke carrying heat from the combustion chamber, have reached a high temperature.

A further object of my invention is to provide an up draught suction in a chimney when cooled.

A further object is to promote rapid and complete combustion in the combustion chamber and to reduce the formation of smoke to a minimum when starting the fire with fresh fuel.

In chimneys and particularly those comprising long metal fiues exposed to the cooling effect of cold air and wind, when a fire is started in the combustion chamber or when a fresh charge of fuel. is fed to the fire bed, the cooled air in the flue acts as a baiile to the gases from the fire and produces smoke and delays the complete combustion of the fuel.

This effect not only results in waste of combustible material but in the escape of large quantities of smoke which besides being very disagreeable and annoying to the neighbourhood, is in many cases a direct offense against municipal by-laws and liable to the infliction of penalities.

By means of the application of this invention to chimneys the above results may be practically eliminated.

The invention consists briefly in providing an electric heater at the outlet of the chimney which can be controlled from a switch in a convenient position.

The invention is parti ularly adapted to be used in connection with my invention patented on the 22nd January, 1929, No. 1,700,018, which provides a metal cap at the outlet of the chimney.

Reference is made to the accompanying drawing in which The single figure shown is a sectional view of a chimney with the invention installed.

The chimney 1, has a metal lining 20 at its 1929. Serial No. 354,899.

outlet 21. Means to heat this lining 20 are shown in the form of a coil 3 of resistance wire mounted on a pad 4: of insulating material such asbestos. The current is supplied through the circuit wires 30 controlled at a convenient point by switch 81.

The particular form of the invention shown in Figure 1, consists of a metal chimney cap 2 having spaced walls 20 and 22, extension 25, inclined cover 23 and outer flange 24:, as shown in United States Patent No. 1,700,018, January 22nd, 1929, with the modification however that the inner wall 20 inclines inwardly to reduce the area of the outlet.

This cap 2 provides an enclosed air chamher.

A short distance below the outlet 21 an asbestos pad 4 is mounted around the outer side of the wall 20 and the heating wire 3 is secured to the pad 4. The terminals of the heating wire 8 are connected to the circuit wires 30 which pass through a porcelain tube 5, a layer of cement 6 and then down the outside of the chimney 1, to the switch 31.

lVith a construction such as above dc scribed, the operation of the invention is as follows hen a fire is about to be started in the furnace or when a fresh charge of fuel is about to be fed to the fire, the switch closed and the current heats the heating wire and this heats tne metal outlet 21. The effect of heating the outlet of the chimney is to produce a suction in the chimney and an increased draught to the fire whereby rapid combustion is secured and the formation of smoke reduced to a minimum.

lVhere the chimney is in the form of a metal flue exposed to the cooling effect of the atmosphere, temperature, or air currents etc. the cooled air in the flue tends to act as a baffle to the gases rising from the fire and the chimney draught is reduced and smoke is produced in quantity.

By means of this invention the cool air in the chimney is rapidly drawn up and expelled.

hen the heated products of combustion have heated the cap sulliciently, the switch is opened and the heating Wires cease to opcrate.

Vhat I claim is 1. In a chimney, a metal surface within the outlet thereof, and means to heat the metal surface independent of the heat of combustion gases.

2. In a chimney, a metal sleeve within the outlet and an electric heater adapted to heat the sleeve.

' 3. In a chimney, a hollow metal cap forming the outlet, and an electric heater mounted within the cap, adapted to heat the outlet portion of the cap.

4:. In a chimney, a hollow metal cap having its inner wall tapered upwardly to the outlet, and an electric heater mounted on the inner wall adjacent the outlet.

5. In a chimney, a hollow metal cap froming the outlet, an insulated heating wire mounted within the cap adjacent the outlet, a current circuit connected thereto and a switch to control the current.

LESTER L. BLANCHARD. 

